Edgar ames turner



E. A. TURNER.

Patented Aug. 12, 1919.

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m m m PISTON FOR INTERNAL COMBUSTION ENGINES. APPLICATION FILED DEC-28.19I1.

UNITED STATES PATENT ()EFICE.

EDGAR AMES'TURNER, or CHICAGO, ILLINOIS, ASSIGNORTO NORTH-WESTERNEXPANDED METAL 00., or CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS.

PIS TON FOR INTERNAL-COMBUSTION ENGINES.

To all whom it may concern:

Be it known that I, EDGAR A ms TURNER, a citizen of the United States,and a resident of Chicago, in the county of Cook and State of Illinois,have invented certain new and useful Improvements in Pistons forInternalecom'bustion Engines, of which the following is a specification.

The present invention relates in general to pistons. and moreparticularly to that type of piston which employs a relativelyelongated. exterior side-wall, body or sklrt having a large bearingsurface against the wall of the cylinder within which it operates, suchtype of piston (being utilized in lieu of construction utilizing apiston having a relatively short side-wall in combina-- tion with across head. More specifically the invention contemplates the provisionof an improved piston structure peculiarly adapted to the conditions ofmodern internal combustion engine practice, though its utility is by nomeans limited to the explosion types of motors.

To the end that my present improvement-s may be best understood by thosewho are skilled in the art to which it pertains, I wish to point outthat I desire to gain all the advantage of light weight, high heatconductivity, and detachability from the plstonhead of the piston-walland associated parts with little or no disturbance of such head,

or of the connecting rod. and wrist pin where the latter is used,without sacrifice of any of the qualities of strength, support,

wear resistance, rigidity, polishability, or

of any of the other elements of e-fliciency in pistons of the best typesknown to me.

It is recognized in modern engineering practice relating to theconstruction of mot'ors, especially multi-cylindered motors forautomobiles, aeroplanes and thelike, where the trend is toward highercompression small cylinder bore and longer piston stroke, that on theone hand greater efiiciency is attained by the use of pistons formed ofthe lighter weight metals such as aluminum or its alloys, but that onthe other hand the longevity in service to be attained by the uses ofiron is sacrificed *by the substitution of the lighter metals in pistonconstruction.

It has been found as a result of experi ence. that pistons formed ofmetals of light weight or alloys thereof, heretofbre employed, are ofrelativelyshort life, (or at Specification of Letters Patent.

Application filed December 28, 1917.

Patentea Aug. 12, 1919.

Serial No. 209,274. I

best require early repairs or replacement as compared with iron pistons)owing to their lack of resistance to wear and mechanical strength,exhibited largely through their inability to afford a permanent tightseat for the piston rings, with ensuant slap, loss of compression,and-oil-leakage. F urthermore, they not only lack the inherent abilityto, take a high mirror-like polish as does cast iron, but on the otherhand, hav ing both a high co-eflicient of heat expansion and a softsurface, they exhibit tendencies to enlarge in cross section, and grabor seize the cylinder walls at extra high engine speed and load. Againwhile light metal or alloy pistons exhibit excellent qualities of heatconduction, their use entails allowance for their high coeflicient ofheat expansion by providing for greater clearance than needed with ironpistons, with ensuant disadvantages at low motor temperatures oflooseness of fit, slap, loss of compression. and leakage of oil upwardpast the-piston-head with resultant carlbon deposits, which tend tointerfere with the action of the piston-rings, and on becomingincandescent to cause pro-ignition of the explosive charge in thecompression chamber. Likewise, such carbon particles, and road du'st,especially when associated with soft metal and the alloys thereof whichremain velvety and wear rapidly, tend to become embedded .in the outerwalls of the piston, which are in frictional contact with the innerwalls of the cylinder, act as abrasive elements with slow but continuouslapping effect on such cylinder walls" causing them, as well as thepiston itself, to become out of round.

Cast iron on the other hand is, in modern 'practice'in this art, open tothe very great objection of excess weight though it presents theadvantages of great strength, rigidity, wear resistance, lowco-eflicient of heat ex pansion, freedom from distortion under heat anda high ability to take and retain a mirror-like polish on frictionalsurfaces such as marks its contact with the interior walls of years ago,this fact requiring when iron is used in constructing the piston, amaterial thickening of the piston head (with consequent further increasein the undesirable factor of weight) in order to provide a sulficientmass of metal to attain the desired degree of heat conductance withresultant lowerinw of temperature on top of the piston.

T 1e principal objects of my present invention therefore are: theprovision of a piston characterized by the employment of a built upconstruction wherein some metal, even if relatively heavy but having arelatively hard and polishable wearing surface and preferably a lowco-efficient of expansion with ensuant freedom from distortion, isemployed for the piston head and external piston body,

. wall or skirt, in combination with some metal having a highconductivity of heat, and preferably one of light specific gravityemployed for the interior core; the. provision of a built-up pistonstructure wherein the piston core is extended up to and abuts againstthe top of the piston so as to transmit heat from the central portion ofthe piston head against which the explosive force of the burning gasesact, and where the heat is most intense; the provision of an improvedform of built-up piston structure comprising separate core or skeletonand head withwall or skirt where. in the parts are readily detachable;the provision of improved means for conducting heat away from the pistonhead and wall and for facilitating the dissipation of such heat; theprovision of an improved form of piston which is characterized not onlyby light weight but also b an improved degree of abilit to conduct t eheat from the piston heat and wall to the connecting rod or pitmanwhereby the dissipation of heat is facilitated, together with such otherobjects as may hereinafter appear. In attaining the objects outlinedabove, and certain additional benefits and advantages to be pointed outbelow, I have provided constructions illustrated in the accompanyingdrawings wherein H Figure 1 is a vertical sectional elevation of apiston embodying my present improvements;

Fig. 2 is a central vertical sectional view of the structure of Fig. 1taken on the line 2'2 therein; and

F igs. 3 and 1 are views similar to those of Figs. 1 and 2, Fig. l beinga view taken on line 1- 1 of Fig. 3, illustrative of a modified form ofconstruction.

Referring now more particularly to the structure of Figs. 1 and 2, itwill be observed that I have here shown my present, improvements appliedto a form, of piston employed in internal combustion engines, wherein,the piston body, wall, or skirt 10 is mounted on a core 11 provided withmeans,

such as the bosses 12 apertured as at 13 for tachment to a connectingrod or pitman 1&

Where a wrist pin, or ball and socket joint,

or other flexible connection is used, I prefer to provide lubricationgrooves, as indicated at 15, which may be conveniently disposed incomplementary passages in the piston wall 10, and in the ribs 16 thatform part of the body of the carrier 11, and give it a skeleton formsuch as is desirable for the sake of lightness. The piston wall 10 isalso provided with such circumferential annular recesses or grooves(indicated at 17) as may be desired for the reception of the pistonrings.

Now it will be apparent on examination of the drawing that in each casethe core or skeleton 11 has a solid top 18 contacting with the centralportion of the piston head heat from the piston head 19 to the core 11.

In-some modern multi-cylindered gas-engines having removable cylinderheads, especially where crank-shafts having large connecting rodbearings and counter-balance weights and crank throws disposed in aplurality of planes are employed, it is desirable that the pistons andany associated parts such as piston rings may be installed from the topsof the cylinders in assembling the engine, or even from time to timewithdrawn therefrom for inspection, cleaning, repair or replacement. Insuch cases, I preferably detachably secure the piston wall or skirt 10to the carrier 11 by means of flat head counter-sunk screws 20 havingthreaded engagement withapertures 21 in one of the ribs 16. Theapertures 21 are preferably arranged immediately over the ance of thecontents of'the firing chamber, a

as well as on the compression strains of eX- plosion strokesmay betransmitted in a straight line between the screws 20 and bosses 21through their connecting rib 16 and directly to the wrist pin 14,instead of transversely thereto with consequent tendency to distortion.The screws 20 may be restrained from accidental rotation by driving asmall portion of the outer edge of the screw into a notch 20.

In Figs. 3 and 4, I have shown a construction similar in certainrespects to that of Figs. 1 and 2, save mainly that but a sin glecentral screw is employed for attaching the head 19 to the core 11.

' This is desirable since any inequalities serve as foci for the depositand retention of carbon particles, tending on accumulation andsubsequent incandescence to become live points of fire and thereby tocause pre-ignition of the compressed charge in the explosion chamber.

On the other hand, the construction of Figs. 1 and 2 presents advantagesto be pointed out, especially in that all strains are transmitted indirect alinement.

In constructing the form of piston above described I preferably form theouter wall or elongated skirtlO of some form of iron or other hardmetal, and the inner core or skeleton of aluminum or of an alloythereof, a ground or other gas-tight joint being formed at some point ofcontact therebetween, such as the seat between the head 19 and thatportion of the top 18 of the core .lying immediately thereunder. Theparallel portions of the members 10 and 11 should fit closely so as togave, as far as possible, a tight telescopic jolnt therebetween at allpoints under normal operating temperatures, owing to the difi'erence inthe relative co-eflicients of heat expansion between the two dissimilarmetals when proper predetermined clearances are used between suchdissimilar metals. Aluminum alloys are very light in weight comparedwith any hard durable metal such as cast iron or steel, and in thisconstruction would constitute the core or skeleton, and thus the bulk ofthe mass of the piston. The outer piston sleeve or wall, fitted closelyinto the core, could be machined both inside and outside and be verythin and light in weight even if made of iron. Aluminum alloy isfurthermore an excellent conductor of heat, and it would in the presentconstruction be a solid integral mass with its upper face in contactwith the central portion of the piston head which has its principalsurface exposed to the spot where most of the heat in the piston isgenerated. Being also in intimate contact with the outer piston slee eon the side walls and having a large area exposed to the cooling splashof the lubricating oil and comparatively cooler air of the crank case,as well as being situated to transmit heat directly down the connectingrod to which it is attached, it provides means of constructing a pistonof lighter weight than is possible, with the lightest feasible cast ironpiston without in the least, however, sacrificing the admirable wearingqualities, low coefiicient of heat expansion, and freedom fromdistortion of the solid cast iron type of piston. At the same time itprovides far better cooling of the piston head than is possible withcast iron. The perfect cylindrical form of the outer piston sleeve orwall, the complete absence of inequalities of thickness in the wall, andof wrist pin bosses, ribs under the piston head, etc., would furthertend to give uniform heat expansion and freedom from distortion, therebypreventing the piston itself from becoming out of round and causinguneven wear or possible scoring to the cylinder walls under heat, andthe piston wall losing its close and even contact with the cylinderwalls.

It will also be seen that in my present construction there is nopossible way for the wrist pin to become misplaced'and cause scoring ofthe cylinder wall, nor does the wrist pin have to be held in place bysuch means as are commonly employed in ordinary piston construction; infact the wrist pin can be allowed to float both in the piston corebosses and in the connecting rod.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent is:

l. A built up bi-metallic piston construction comprising, incombination, an outer iron wall and head, and an inner supporting coreof aluminum alloy contacting with said head, adjacent the center thereoffor transmitting heat therefrom.

2. A builtnp bi-metallic piston construction comprising, in combination,an outer wall and head,- and an inner supporting core contactingtherewith adjacent the center of the head for transmitting heattherefrom, the said core being formed of metal of relatively high heatconductivity as compared with that of the head.

3. A built up bi-metallic piston construction comprising, incon'rbination, an outer iron wall and head, an inner supporting core ofalluminum alloy detachably contacting with said head for transmittingheat therefrom.

4;. A built up bi-metallic piston construction comprising, incombination, an outer wall and head, and an inner supporting core havinga portion extending toward and contacting with said head at some pointfor transmitting heat therefrom, said core being formed of metal ofrelatively high heat conductivity as compared with that of the head.

5. A built up bi-metallic piston construction comprising, incombination, an outer wall and head, and a skeleton inner supportingcore contacting with said head adjacent the center thereof fortransmitting heat therefrom.

6. A built up bi-metallic piston construction, in combination, an outerwall and head and an inner core having a portion extending toward andcontacting with said head at some point for transmitting heat therefrom,the said core detacha'bly supporting said head and wall, and beingformed of metal of relatively high conductivity as compared with that ofthe head.

7. A built up bi-metallic piston construction comprising, incombination, an outer wall and head, and an inner core having a portionextending toward and contacting with said head at some point fortransmitting heat therefrom, the said core being formed of metal ofrelatively high heat conductivity as compared with that of the head andhaving a relatively great coefficient of expansion and detachablysupporting said head and wall.

8f A built up bi-metallic piston construction comprising, incombination, an outer iron wall and head, and an inner core of aluminumalloy contacting at said head adjacent the center thereof fortransmitting heat therefrom, the said core and head being detachablysecured together and provided with means for fixing them inpredetermined relation.

9. A built up bi-metallic piston construc tion comprising, incombination, an outer iron wall and head, and an inner supporting coreof aluminum alloy contactingwith said head adjacent the center thereoffor transmitting heat therefrom, the said core and head being detachablysecured together and provided with means for fixing them inpredetermined relation, said last mentioned means being operable fromthe head end of the piston.

10. A built up bi-metallic piston construction comprising, incombination, an outer wall and head, and an inner core contacting withthe head at some point and provided With'means for supporting a wristpin and connecting rod'carried thereby, and means for detachablyconnecting said core and head, two of said last mentioned elements beingarranged in alinement whereby strains may be transmitted in a directline.

11. A built up bi-metallic. piston con-- struction comprising, incombination, an outer Wall and head, and an inner core provided withmeans for supporting a wrist pin and connecting rod carried thereby, andmeans for detachably connecting said core and head, two of said lastmentioned elements being arranged in alinement whereby strains may betransmitted in a direct line, and said core being formed of metal of arelatively high heat conductivity as compared with that of the head.

12. A built upbi-metallic piston construction comprising, incombination, an outer wall and head, and an inner core provided withmeans for supporting a wrist pin and connecting rod carried .thereb andbeing in contact with said head ad acent the center thereof, said corebeing formed of metal of a relatively high heat conductivity as comparedwith that of the head and thereby adapted to transmit heat from saidhead to said wrist pin and the connecting rod.

13. A built up bi-metallic piston construction comprising, incombination, an outer wall and head, and an inner core detachablysupporting said outer wall and head and being in contact with said headadjacent the center thereof and provided with means for supportin aWrist pin and connecting rod carried t ereby, said core being formed ofmetal of a relatively high heat conductivity as compared With that ofthe head and thereby adapted to transmit heat from said head to thewrist pin and connecting rod.

14. A built up bi-metallic piston construction comprising, incombination, an outer wall and head, an inner core detachably supportingsaid outer wall and head and being in contact with said head adjacentthe center thereof, and provided with means for supporting a Wrist pinand connecting rod carried thereby, and means for connecting said coreand head, the said core being formed of metal ofa relatively high heatconductivity as compared with that of the head and thereby adapted totransmit heat from the head to the Wrist pin and connecting rod. V

15. A built up ,bi-metallic piston construction comprising, incombination, an outer iron shell forming the piston head, an innersupporting core of aluminum alloy having a portion projecting toward andcontacting with said head at some point for transmitting heat therefrom,and means for preventing relative movement therebetween.

16. A built up bi-metallic piston construction comprising, incombination, an outer shell forming the piston head, and an inner coreadapted to engage a wrist pin and connecting rod carried thereby,provided with a portion projecting toward and connecting with said headat some point for transmitting heat from said head to the wrist pin andconnecting rod.

17. A built up bi-metallic piston construction comprising, incombination, an outer shell forming the piston head, and an innersupporting core having telescopic relation with said shell andcontacting with said head adjacent the center thereof, for transmittingheat therefrom,

18. A built up bi-metallic piston construction comprising, incombination, an outer shell forming the piston head, and an innersupporting core having telescopic relation with said shell andcontacting with the head adjacent the center thereof, the said corebeing 'formed of metal having a relatively high heat conductivity and arelatively high co-efficient of heat expansion as compared with that ofthe head whereby, it is brought into intimate contact with said shellunder normal operating temperatures and I thereby adapted moreeffectively to transmit heat from said head.

19. A built up piston construction comprising, in combination, an outershell of iron and an inner supporting core of aluminum alloy contactingwith the head portion of said shell adjacent the center thereof forconducting heat therefrom.

20. Abuilt up bi-metallic piston construction comprising, incombination, an integral outer shell and head, an inner supporting corecontacting therewith at some point adjacent the center of the head fortransmitting heat from the said head, and means for detachablyconnecting head and core.

21. A built up bi-metallic piston construction, comprising, incombination, an integral outer shell and head, an inner supporting corecontacting therewith at some point adjacent the center of the head fortransmitting heat from the said head, and threaded means fordetachablyconnecting said head and core.

22. A built up bi-metallic piston construction, comprising, incombination, an integral shell and head, an inner core contactingtherewith at some point adjacent the center of the head for transmittingheat from said head and threaded means operable from the head end of thepiston for detachably connecting said head and core.

23. A built up bi-metallic piston construction, comprising, incombination, an integral outer shell and head, an inner core contactingtherewith at some point adjacent the center of the head for transmittingheat from said head, and means operable from the head end of said pistonfor detachably connecting said head and core.

24. A built up bi-metallic piston construc-' tion, comprising, incombination, an integral outer shell and head, and an inner core forsupporting said shell and head, said core be ing in contact with thehead at some point for transmitting heat therefrom and said shell beingof substantially cylindrical forminternally, throughout substantiallyits entire length.

25. A built up bi-metallic piston construction comprising, incombination, an integral outer shell and head, an inner core forsupporting said shell and head, said core being in contact with the headat some point for transmitting heat therefrom, and said shell being ofsubstantially cylindrical form internally, such internal surface beingsubstantially free from internal projections.

26. A built up bi-metallic piston construction comprising, incombination, a connecting rod or pitman, an iron outer Wall and headforming a shell, an inner core of aluminum alloy contactingv with said.head adjacent to the center thereof for transmitting heat therefrom,-thesaid core being constructed and arranged for the attachment of the shellto the connecting rod or pitman.

27. A built up bi-metallic piston construction comprising, incombination, an outer wall and head,'and an inner supporting core ofaluminum alloy contacting with said head and wall for transmitting heattherefrom.

28. In a fluid pressure engine including a cylinder, a pistonreciprocable therein, and a connecting rod or pitman operable by saidpiston, the said piston having an iron outer wall and head forming ashell, and an inner core of aluminum alloy supporting said shell andconnecting it to said connectingrod or pitman and adapted to conductheat away from said shell and cylinder wall and to said pitman orconnecting rod.

29. In a flu1d pressure engine lncludlng a cylinder, and a pistonreciprocable therein,

-a connecting rod or pitman operable by said piston, the said pistonconstruction comprising an inner core of relatively high conductivityand light weight, and an outer sleeve fitted thereupon supported therebyand contacting with the walls of the cylinder, said core being adaptedto transmit heat from the-piston and cylinder walls to the connectingrod or pitman.

30. A built up bi-metallic piston construction comprising, incombination, an outer wall and head of relatively low heat conductivity,and an inner supporting core of relatively high conductivity fortransmitting heat from said Wall and head.

31. A built up bi-metallic piston construction comprising, incombination, an outer shell forming the piston head and skirt, and aninner supporting core having a telescopic relation with said skirt fortransmitting heat therefrom.

In testimony signed my name.

EDGAR AMES TURNER.

